Function crypto_sign_final_create 

pub fn crypto_sign_final_create(
    state: SignerState,
    signature: &mut Signature,
    secret_key: &SecretKey,
) -> Result<(), Error>

Finalizes the incremental signature for state, using secret_key, copying the result into signature upon success, and consuming the state.

Errors

The fixed-size signature and secret-key types satisfy the current implementation’s requirements, so this function does not return an error in normal use. The Result is retained for API compatibility.